Court ruling threatens extended Mühleberg operation

A Swiss court has ruled that the Mühleberg nuclear power plant can only operate until mid-2013 in an extraordinary move that overturns a 2009 decision by the environment ministry to issue an unlimited-duration operating licence.

A Swiss court has ruled that the Mühleberg nuclear power plant can only operate until mid-2013 in an extraordinary move that overturns a 2009 decision by the environment ministry to issue an unlimited-duration operating licence. However, the ruling is not yet legally binding and the plant owner is still to react.

Mühleberg (Image: BKW)

In December 2009, the Department of the Environment, Transport, Energy and Communications (DETEC) granted BKW FMB Energy - operator of the Mühleberg plant - an indefinite extension to its licence on condition that the plant continues to meet national nuclear safety requirements. Its licence had previously been due to expire on 31 December 2012.

However, in response to a complaint brought before it by local residents, the Federal Administrative Court has now ruled that several factors impose a limit to the plant's lifespan. In its ruling, the court said: "The state of the core shroud, the incomplete assessment of the plant's resistance to earthquakes and the lack of cooling possibilities independent of the River Aare do not allow for the operation of Mühleberg beyond mid-2013."

A spokesman from the Swiss Nuclear Forum explained to World Nuclear News that the core shroud issue mentioned by the court relates to some cracked welding on a mechanism that guides the flow of water around the fuel assemblies. This, he said, had already been repaired.

The court ruled that the Mühleberg plant must stop operating by 28 June 2013. It also decreed that BKW must now submit a comprehensive maintenance concept for the long-term operation of the plant to DETEC, together with a new application to extend its operating licence for a specified period. BKW would be required to explain how it would address the deficiencies highlighted by the court as well as how much these measures would cost. Mühleberg is a 372 MWe boiling water reactor (BWR) which began commercial operation in 1972.

BKW, noting that the ruling is not yet legally binding, said that it will examine the court's decision in detail and decide on how it will proceed. The company could appeal the court's ruling in the Federal Court in Lausanne. BKW also noted that it is already in the process of drawing up a general maintenance concept for Mühleberg with a view to the long-term operation of the plant. The Swiss nuclear regulator, the Swiss Federal Nuclear Safety Inspectorate, acknowledged the court's ruling. While noting that it does not actually actually cancel the plant's operating licence, it said that it extends the licence by six months from its previous expiry date.

Switzerland's five nuclear reactors generate some 40% of its electricity, but following the nuclear accident at Fukushima in March 2011 the Swiss parliament resolved not to replace any reactors at the end of their lives, which would effectively see nuclear phased out by 2034. Should Mühleberg be shut down in 2013, instead of as expected around 2022, the rate and cost of the country's nuclear phaseout could increase substantially. It is unclear how this ruling could effect the operating lives Switzerland's other operating reactors - Beznau units 1 and 2, Gösgen and Leibstadt. The Beznau units and Gösgen are pressurized water reactors which have been in operation since 1969, 1971 and 1979, respectively. Leibstadt is a BWR which started operation in 1984.

Researched and written
by World Nuclear News